Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Overlay Grafting Prof. Mahmoud El Samaa Prof. of ORL, head of ENT Dep Ain Shams University Edited by Prof. Mohamed El Begermy

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Skin Incision Hockey stick skin incision This part exposes fascia This part exposes mastoid

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Exposure& harvesting temporalis fascia

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Canal Skin incision Incision at Tympanomastoid suture Incision at Tympanosquamous suture Vascular strip Incision 2mm from annulus Incisions are made along the two suture lines the tympanosquamous and tympanomastoid suture. This area demarcates the vascular strip which is the area of the canal skin that covers the superior and postero- superior portions of the canal.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Elevation of vascular strip The skin of the vascular strip is elevated laterally keeping it pedicled superiorly Dierection of elevation Vascular strip

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Elevation of the vascular strip Skin incision Dissection elevation

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane A circumferential incision is made in the outer third of the bony canal with a beaver knife, connecting the two incisions.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane The canal skin is elevated from the bone posteriorly as far as the annular ligament. The dissection continues anteriorly and inferiorly parallel to the annular ligament to avoid elevating it the tympanic membrane remnant.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Elevation of anterior inferior & suprior skin 3- Elevation is done in such a way that the remnant is de- epithelialized in continuity with the canal skin. Red arrow. The skin is removed from the ear and kept moist in saline 1- The dissection proceeds superficial to the fibrous layer along the inferior and anterior walls, 2- Dissection then proceeds along the superior canal wall and carried medially until the skin has been freed of all its attachments.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Enlargement of the ear canal This is done by removal of the anterior canal bulge with a curette or a drill. Advantages : Removal of the anterior bulge enlarges the field of surgery. The anterior sulcus is exposed to allow de-epithelialization and satisfactory graft placement. The acute angle in this area is opened, preventing post- operative blunting. There is no hidden area from post-operative observation.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Placement of the fascia: Grafting begins after all squamous epithelium is removed. The fascia is put under the manubrium and a slit is cut to allow its placement. The fascia is placed over the perforation (on the outer surface of the tympanic membrane remnant) and is adjusted anteriorly and inferiorly. Be sure that it does not extend onto the bone wall anteriorly, to avoid blunting problem. Replacement of canal skin The canal skin is replaced to cover the bone from which it was removed. It is positioned slightly more medially, however, allowing it to overlap the fascia by a few millimeters.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Return the vascular strip in its place

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane The canal is packed securely with pledgets of gelfoam

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Advantages of Onlay grafts 1- High graft take rate. 2- Better exposure.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Disadvantages More difficult in mastering the technique. Higher incidence of healing problems interfering with the functional result including: i.Lateralization of the graft ii.Blunting in the anterior sulcus iii.Excessive membrane thickness iv.Epithelial pearls

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Lateralization of onlay graft correct position, Definition: lateral displacement of the graft away from maleus handle. This results if the graft is not firmly seated in place or lateral traction by the healed fibrous tissue How to avoid: Absolute hemostasis. Discontinuation of the nitrous oxide 30 minutes before grafting. The placement of the graft under the maleus handle. Avoid blowing of the nose and Valsalva’s post- operatively. Lateralized onlay graft, Blunting

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane II- Blunting of anterior meatal angle Blunting of anterior meatal angle Definition: formation of fibrous tissue at the anterior meatal angle bdeep to the anterior part of the graft. This decreases the vibrating area of TM graft This occurs if the graft is not accurately placed so that it does not extend to the anterior wall. How to avoid: 1- Removal of the anterior hump to open the anterior angle. 2- Avoid placement of the fascia onto the anterior canal bone. 3- Be sure that the replaced canal skin averlaps the graft a few millimeters anterosuperiorly.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane Other complications III- Excessive membrane thickness: This may be due to excessive thicknes of the fascia graft, delayed healing of the canal, post-operative infection and ET insufficiency. IV- Epithelial pearls: This usually results from inadequate de-epithelialization of the remnant or adjacent bone. It develops slowly between the remnant and fascia. It is usually localized and inferior and it is marsupilized as soon as it is recognized.

Temporal Bone Laboratory Ain Shams University Overlay Grafting of Tympanic membrane